What can nest-building birds teach us?

For many years nest building in birds has been considered a remarkable behaviour. Perhaps just as remarkable is the public and scholarly consensus that bird nests are achieved by instinct alone. Here we take the opportunity to review nearly 150 years of observational and experimental data on avian nest building. As a result we find that instinct-alone is insufficient to explain the data: birds use information they gather themselves and from other individuals to make nest-building decisions. Importantly, these data confirm that learning plays a significant role in a variety of nest-building decisions. We outline, then, the multiplicity of ways in which learning (e.g., imprinting, associative learning, social learning) might act to affect nest building and how these might help to explain the diversity both of nest-building behaviour and in the resulting structure. As a consequence, we contend that nest building is a much under-investigated behaviour that holds promise both for determining a variety of roles for learning in that behaviour as well as a new model system for examining brain-behaviour relationships.